Clinical Challenge: Blisters on Finger

Herpes simplex virus (HSV) is often first acquired in childhood.1 The causative viruses belong to the Herpesviridae family and are known as HSV-1 and HSV-2. Infections involving the lips are referred to as fever blisters or cold sores. In 1959, Stern...

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Herpes simplex virus (HSV) is often first acquired in childhood.¹ The causative viruses belong to the Herpesviridae family and are known as HSV-1 and HSV-2. Infections involving the lips are referred to as fever blisters or cold sores. In 1959, Stern used the term herpetic whitlow to describe a blistering finger eruption afflicting multiple nurses.²

Primary infection is caused by direct inoculation of HSV-1 or HSV-2 through broken skin.³ Recurrent cases result from reactivation of the latent virus months to years following the primary infection.⁴ Herpetic whitlow is most common in children who place fingers in their mouths, health care providers exposed to oral secretions, and athletes.⁵

The diagnosis is usually made by history and examination with the most common presentation being painful vesicles of clear fluid on an erythematous base occurring within 3 to 4 days of virus exposure.⁶ Occasionally fluid may become turbid or opaque over time, with vesicles coalescing into bullae. The infection usually affects only 1 finger but cases involving multiple digits have been reported.

Risk factors for the disease include nail trauma, exposure to secretions, and previous HSV infections.⁷ Patients may experience a prodrome of mild burning, itching, or discomfort at the inoculation site several days prior to eruption.⁸ Primary herpetic whitlow is self-limiting in most immunocompetent patients, with resolution occurring within 2 to 4 weeks.⁹ The vesicles commonly progress to dry crusts with pain resolving and no skin changes remaining.

Infection of the fingertip pulp (bacterial felon), fingertip cellulitis, and bacterial paronychia are conditions that should be considered in the differential diagnosis.⁶ In cases of uncertainty, Tzanck smear, viral culture, or polymerase chain reaction testing of fluid from a vesicle can confirm the diagnosis. Scraping and staining of lesions will show the presence of multinucleated “balloon” giant cells, with nuclei that appear blue and homogenous.¹⁰

Treatment is aimed at halting viral replication, symptomatic pain relief, and prevention of bacterial superinfection.¹¹ Oral antivirals may be considered for patients with recurrent lesions, those presenting with symptoms less than 48 hours, or immunocompromised individuals. These include acyclovir, valacyclovir, or famciclovir with oral antibiotics reserved for cases of secondary digit infection. Incision and drainage are contraindicated as manipulation can increase the likelihood of bacterial superinfection and cause viremia.¹²

Patient education about viral spread to other locations and other individuals through direct contact is critical. Shedding of viral particles is present until the epidermal lesion is healed, therefore patients should be advised to keep a protective barrier over the vesicles.

Alexandra Stroia, BS, is a medical student at the Lake Erie College of Osteopathic Medicine. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Geisinger Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.

References

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2. Stern H, Elek SD, Millar DM, Anderson HF. Herpetic whitlow, a form of cross-infection in hospitals. Lancet. 1959;2(7108):871-874. doi:10.1016/s0140-6736(59)90804-9
3. Adışen E, Önder M. Acral manifestations of viral infections. Clin Dermatol. 2017;35(1):40-49. doi:10.1016/j.clindermatol.2016.09.006
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6. Rerucha CM, Ewing JT, Oppenlander KE, Cowan WC. Acute hand infections. Am Fam Physician. 2019;99(4):228-236.
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8. Klotz RW. Herpetic whitlow: an occupational hazard. AANA J. 1990;58(1):8-13.
9. Patel R, Kumar H, More B, Patricolo M. Paediatric recurrent herpetic whitlow. BMJ Case Rep. 2013; 2013:bcr2013010207. doi:10.1136/bcr-2013-010207
10. Singh A, Preiksaitis J, Ferenczy A, Romanowski B. The laboratory diagnosis of herpes simplex virus infections. Can J Infect Dis Med Microbiol. 2005;16(2):92-98. doi:10.1155/2005/318294
11. Arora R, Chattopadhyay S, Agrawal S, Chatterjee S. Self-inflicted herpetic whitlow. BMJ Case Rep. 2014;2014:bcr2013201817. doi:10.1136/bcr-2013-201817
12. Feder HM, Long SS. Herpetic whitlow. Epidemiology, clinical characteristics, diagnosis, and treatment. Am J Dis Child. 1983;137(9):861-863. doi: 10.1001/archpedi.1983.02140350035009